The speed of connecting and disconnecting hundreds of wellbore tubulars makes a great difference in the time required to drill and bring a well onto production. For instance, it is normally necessary to insert and remove the drill string several times during the drilling process wherein numerous threaded connections of the wellbore tubulars (e.g., drilling pipe) have to be made or broken. Due to the high cost of drilling (e.g., rig time), it is desirable to make or break a connection as quickly as possible.
One style of devices for making and breaking wellbore tubulars includes a frame that supports up to three power wrenches and a power spinner each aligned vertically with respect to each other. Examples of such devices are disclosed in U.S. Pat. Nos. 6,722,231; 6,634,259; 5,386,746; and 5,060,542 which are incorporated herein by reference. Additional examples described in U.S. Pat. Nos. 7,455,128; 7,114,235; and 6,776,070 are also incorporated herein by reference. These devices spin one tubular with the power spinner at a relatively high speed but at a relatively low torque while holding another tubular fixed with one of the power wrenches. Traditionally, when making tubulars, the spin process continues until the two threaded tubulars shoulder up, e.g. until a pin shoulder engages the box shoulder. After shouldering up, the power spinner is stopped and two of the power wrenches are used to apply high torque to the connection or joint so that the joint is securely fastened and sealed. The application of high torque rotates the tubulars with respect to each other but at a very low speed of rotation. Once the tubulars are shouldered it is only necessary to rotate a relatively small amount so the low speed of rotation does not slow the process down. Likewise when breaking tubular connections (e.g., pipe joints), two power wrenches apply a high torque to initially break the connection. Then the power spinner spins the top tubular with respect to the lower tubular held by a power wrench until the threaded connection is completely disconnected. In this manner, the connectors can be quickly made or broken to save considerable time and money while drilling a well.
Traditional drill pipe threaded connections facilitated shouldering the pin and the box utilizing the high rotation and low-torque spinners. However, current wellbore tubular threaded connections and wedge thread designs require increasing torque as the pin advances into the box to shoulder the connection. Examples of newer wedge thread connections are described in U.S. Pat. Nos. 7,527,304 and 6,682,101. The result is that the high-speed spinner cannot fully advance the pin into the box requiring additional rotation of the tubular in the torque cycle with the power wrench. For example, a torque cycle for a historically utilized drill pipe may require rotation of the tubular of approximately 20 to 45 degrees, wherein the newer tapered thread connections may require rotation in the torque cycle of about one-hundred and fifty degrees to about two-hundred degrees or more to achieve the proper torque utilizing the prior make and break devices. The increased rotation required in the torque-cycle often requires multiple grip and release operations to achieve the total rotation required. Gripping the tubular, rotating, releasing the grip, repositioning the tong and repeating the process is not only a time-consuming and expensive process but it also can damage the tubular and/or result in an insufficient connection that may result in a string failure and or galling of the threads.
During assembly (e.g., make-up) and disassembly (e.g., break-out) of the threaded connection there is no requirement for lateral (e.g., side, transverse, normal to the tubular axis) forces to be applied to the connection and, in fact such forces can have serious detrimental effects. Frictional forces due to lateral forces cause false torque readings and can cause premature thread galling. The lateral forces can actually bend the tubular. Application of lateral forces during tightening can also cause the connection to tighten off center, which can result in loss of the connection's fluid seal. The prior art tubular joining devices impose linear, lateral (e.g., side-load) forces on the threaded connection.
There is a continuing desire to provide a tubular make and break device that promotes tubular connection efficiency. It is a desire to promote higher torque spinning cycles. It is a further desire to minimize side loading on the threaded connection during the spinning cycle and/or the torque cycle. It is a still further desire to minimize box distortion while spinning up the tubular connection. It is a further desire to provide continuous rotation during the torque-cycle.